The present invention relates generally to rotary regenerative air heaters, and more particularly, to an improved arrangement for accessing and removing element baskets from a rotary regenerative air heater.
A rotary regenerative air heater essentially comprises a rotor that carries heat transfer material that is alternately rotated first into a hot gas stream to absorb heat therefrom and then into an airstream to impart heat thereto. The heat exchange material carried by the rotor generally comprises a mass of heat absorbent plates. These plates are assembled in an orderly array and positioned in an element basket that firmly holds the plate in a predetermined space relationship in order that they may be easily handled and arranged in the rotor of the air heater.
Hot gases, usually generated by combusting a fossil fuel in a furnace, pass from the furnace through a damper and a toggle duct into the air heater and thence over the heat absorbent material contained therein. The toggle duct is disposed between the air heater and the furnace exit gas duct and serves to isolate forces generated by furnace expansion so that the air heater is not subjected to and damaged by those forces.
As the gas flows through the heat absorbent material, the heat absorbent material may become loosened in the element baskets, corroded, and covered with particulate material in the gases. Therefore, it is necessary that the element baskets be periodically removed and replaced. Heretofore, it has necessary to provide a significant amount of head room above the air heater between the air heater gas inlet and the gas damper and toggle duct in order that a trolley mechanism may be installed to permit element basket to be lifted from the air heater and removed. Typically, five to six feet of head space was required on prior art air heaters.